Scale Setup

Scale

Idea

Use a regular scale for 10€, mod it to use the internals (and optional the original case).

Example shopping list

• HX711: https://www.amazon.de/gp/product/B07MY2PBY4/ref=ppx_yo_dt_b_asin_title_o03_s00?ie=UTF8&psc=1 (Hint: this breakout is rather big, there are much smaller ones. But these are the once I am using)
• Scale 500g: https://www.amazon.de/gp/product/B072QYDYDF/ref=ppx_yo_dt_b_asin_title_o05_s00?ie=UTF8&psc=1

3D Printer models (optional)

• made by Tobias
• made by Hoondie!! Many thanks

Sample pictures/movies

• https://github.com/medlor/bleeding-edge-ranciliopid/tree/master/3d-models/PerfectCoffeePid-Scale

userConfig

just enable the setting in userConfig.h

#define SCALE_SENSOR_ENABLE                 1     // 0=Off (default), 1=On  (only HX711 supported)
#define SCALE_SENSOR_DATA_PIN              17     // HX711 Data Pin
#define SCALE_SENSOR_CLK_PIN               23     // HX711 Clock Pin
#define SCALE_SENSOR_CALIBRATION_WEIGHT    167.0  // any known weight which is used for calibration (in gram)
#define SCALE_SENSOR_CALIBRATION_FACTOR    5305.0 // manually determined calibration factor (initial 1.0)

Initial setup

1. enable calibration mode with LOGGING

#define DEBUGMODE // to enable Debug uncomment this line. Afterwards you can connect via telnet to port 23 to see debug logs.
#define ENABLE_CALIBRATION_MODE 1 // 0=off (default). 1=on. If on, PID is disabled and CALIBRATION information is logged in DEBUG log (eg. CONTROLS_CONFIG, WATER_LEVEL_SENSOR, SCALE_SENSOR)

1. Set SCALE_SENSOR_CALIBRATION_WEIGHT (in grams) in userConfig.h to any object for which you know exactly the weight (eg espresso cup)
2. Flash
3. remove any (additional) weight from the loadcell
4. start maschine
5. open the LOG (see wiki)
6. wait past 15seconds start time
7. Put the object which matches SCALE_SENSOR_CALIBRATION_WEIGHT on the loadcell
8. Check the LOG. It will calculate the correct SCALE_SENSOR_CALIBRATION_FACTOR which you have to use in userConfig.h .
9. Set ENABLE_CALIBRATION_MODE 0, flash, restart and enjoy.